Parosmia: Pathophysiology and Management.

PURPOSE OF REVIEW: Parosmia is a qualitative olfactory disorder in which there is a mismatch between the memory of an odor and the actual experience triggered by an odor. There has been a surge in parosmia-related publications since the COVID-19 pandemic. This review summarizes the latest clinical findings, theories on pathophysiology and potential treatment options.

RECENT ADVANCES: Potential models of parosmia include peripheral or central hypotheses, which refer to aberrancies in olfactory neuron regeneration or information processing in central olfactory centers respectively. This leads to an incomplete or disorganized pattern of olfactory information relay. Studies using gas chromatography and functional magnetic resonance imaging have identified molecular triggers and intracranial functional connectivity patterns in parosmia respectively. Parosmia tends to occur in a delayed fashion after virus-induced anosmia. It may run a protracted course, but typically improves over time. Currently there are no generally approved, objective ways to ascertain the presence and measure the extent of parosmia. Evidence-based treatment for parosmia remains elusive. In some people, this can lead to health and quality of life issues.